| Through integrating the steel girder and the concrete slab with shear connectors, steel-concrete composite beam has been widely used in the structural and bridge engineering. Compared with traditional concrete structures or steel structures, this new-type composite structure has its particular mechanical performances.With intensive discussion about material nonlinear behaviors of steel and concrete, and the slip performance of shear connectors, the studies about whole-process nonlinear analysis of steel-concrete composite beam are carried with Concrete Structures Bi-NonLinear Analysis (CSBNLA) software in the present thesis. The influences of concrete cracking and interface slip on structural behaviors of steel-concrete composite beam are mainly concerned.Then, the time-variant behaviors of steel-concrete composite beam are investigated in the present thesis. The effects of creep and shrinkage of concrete on structural deformation and stress are studied. Moreover, the influences of arrangement of shear connector on long-term behaviors of steel-concrete composite beam are also studied.Furthermore, the nonlinear and the time-variant behaviors of prestressed steel-concrete composite beam are analyzed. With whole-process finite element analysis, the nonlinear responses of deformation, stress of steel girder and concrete slab, interface slip, and so on are studied. Meanwhile, the long-term effects of prestressed steel-concrete composite beam caused by creep and shrinkage of concrete are investigated. Parameter analysis concerning with those above works is also carried.Finally, numerical simulation about a practical prestressed steel-concrete composite beam bridge with span6×80m is carried in the thesis. The influences of interface slip on the structural behaviors during construction process and long-term behaviors caused by creep and shrinkage are studied. Meanwhile, with nonlinear finite analysis approach, the ultimate resistance capacity of this bridge is determined. |
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